By convention, this type of the air bag device includes a folded air bag, an inflator for supplying gas to the air bag to inflate the bag, a pad for covering the folded air bag, and a bag holder for holding the air bag, the inflator, and the pad as disclosed in Japanese Patent Publication No. Hei. 4-138953 and the like. The bag holder has a bottom wall with an insertion hole into which the inflator is inserted from the lower side of the bag holder. The inflator is provided with a flange that is in contact with a location on the bottom wall of the bag holder that is close to the insertion hole of the bottom wall.
A plural number of mounting holes are formed in the bottom wall of the bag holder and the flange of the inflator. To couple the inflator into the bag holder, those holes of the holder and the inflator are aligned with each other, bolts are inserted into the holes, and nuts are applied to the bolts.
As described above, in the conventional air bag device, the flange is formed on the inflator. The plural number of mounting holes are formed in the flange. The mounting holes must be large enough to receive the bolts. Therefore, the flange must be wide so as to allow the large holes to be formed therein. This results in increase of the weight of the inflator.
The conventional inflator of which the outer surface is made of metallic material, e.g., aluminum alloy, is formed by mold forging of the metallic material. The flange of the inflator is also formed in a hammering manner, during the mold forging process. Therefore, several kinds of molds are required. Further, mounting holes are formed in the thus formed flange. Thus, the manufacturing work of the conventional inflator requires a number of manufacturing process steps and a high cost to manufacture.
Before the vehicle is disused, the inflator must be removed. In this case, a worker unscrews a number of nuts and removes the bolts. Thus, much work is required for the inflator removal.
Another inflator-bag holder coupling structure is disclosed in Japanese Patent Publication No. Hei. 4-26654. In the structure, the bolts and nuts are not used, while a retainer with clamping pawls is used. The clamping pawls are caulked to couple the inflator with the bag holder. Much labor is required to remove the inflator thus clamped.